a. and sb. Obs. [f. prec. + -AN.]
 
  A.  adj. Belonging to the ecclesiastical sect or party of the ACEPHALI.
 
  B.  sb. A member of this sect.
 
1586.  T. Rogers, 39 Art. (1607), 54. Detestable therefore is the error of the Acephalians, who denied the properties of the two natures in Christ.